This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goal of this project is to determine the feasibility of Diffraction Anomalous Fine Structure (DAFS) experiments with protein crystals. In initial approaches to test if the equivalent short range structural information as an EXAFS experiment and the same structural and spectroscopic sensitivity as an XANES experiment may be observed using DAFS, 10 degrees of diffraction data were collected at 4 eV steps in energy across the Fe K-absorption edge using a crystal of P6 myoglobin. Data analysis is underway. From these initial experiments, it was evident that DAFS experiments could benefit from the development of specific data collection scripts or a specific data collection GUI in Blu-Ice. In the future, we plan to use DAFS to simultaneously study two atoms of the same element which occupy nonequivalent sites in a crystal.